This section provides background information related to the present disclosure which is not necessarily prior art.
In general, compressors in the automotive sector are associated especially with the desire for an increase in the power and efficiency of an internal combustion engine of a motor vehicle.
One of the probably best known embodiments of a compressor is the exhaust turbocharger. The exhaust turbocharger is used to ensure an adequate quantity of combustion air in the cylinders of the internal combustion engine by compressing ambient air or an ambient air/exhaust gas mixture and thus supplying the cylinders with this combustion air at excess pressure.
In general, exhaust turbochargers consist of an exhaust turbine and a compressor wheel, wherein the exhaust turbine and the compressor wheel are arranged on a common shaft. The exhaust turbine converts the heat and kinetic energy of the exhaust gas from the internal combustion engine into rotational energy. This rotational energy is transferred via the common shaft to the compressor wheel. By means of the compressor wheel, ambient air or a mixture of ambient air and exhaust gas is drawn in and compressed. It is thereby possible to achieve a higher working pressure for the same temperature in the cylinder of the internal combustion engine.
As long as there is sufficient exhaust gas flowing in on the side of the internal combustion engine and driving the exhaust turbine, the speed of rotation is sufficient to bring about an excess pressure on the intake side. However, when accelerating the motor vehicle, for example, the turbo may respond with a delay (even) at relatively high speeds of rotation—this state being commonly known as “turbo lag”.
There are many approaches to counteracting the occurrence of turbo lag. For example, the inertia of the exhaust turbine can be reduced by making it smaller. Although this lowers the efficiency of the turbo, the exhaust turbine can be driven even by a weak exhaust gas flow.
Another approach in this context is the use of an (additional) electrically driven compressor (electric compressor), for example, said compressor operating independently of the exhaust gas flow of the internal combustion engine.
The publication WO 99/10654 describes an electrically driven compressor, for example, wherein the compressor and the electric drive motor are arranged coaxially with one another on a shaft and are accommodated in a common housing. In particular, the primary object here is to specify a compressor which is of as small construction as possible.
To be able to ensure safe and trouble-free operation of the electric motor, fault-free operation of the control unit is necessary in particular, and this, in turn, entails adequate cooling of the control unit or electronic modules of the control unit. The primary consideration here is the desire to cool the electronic modules of the control unit of the electric compressor without significant additional expenditure on construction and in a way which saves as much space as possible.
Different approaches to cooling electronic components are known from the prior art.
Thus, document DE 10 2007 005 233 A1, for example, describes a power module having at least one semiconductor chip arranged on a substrate and having electrical connections leading to the outside. The semiconductor chip arranged on the substrate and some of the connections are coupled to give close thermal contact with an electrically insulating material of good thermal conductivity that is sealed off with respect to the outside. The material is arranged around the substrate and the semiconductor chip in such a way that a flat structural element is formed that can be coupled to a cooling medium, with the exception of the side with the contacts leading to the outside. It is necessary here to wrap the entire power module with thermally conductive material and to seal it hermetically to enable the power module to be inserted into a cooling duct.